Citation

Brydia RE, Pietrucha MT. Transp. Res. Rec. 1994; 1445: 189-197.

Copyright

(Copyright © 1994, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

For years researchers have attempted to conclusively define values to be used for perception-reaction (PR) times for highway design and operations. Several empirically based studies have confirmed values that are used in different design guides and manuals. However there still appears to be no final agreement on what values should be used for various design purposes. PR time is an essential element in determining intersection sight distance (ISD) requirements. Although there has been much discussion of the appropriate values of PR times that should be used for this purpose, an understanding of the relative influence of PR time on ISD would help to determine whether very exact PR times are needed to adequately design intersections. Previous work on the assessment of appropriate PR times is reviewed, and the influence of varying PR times on the determination of Case III ISD values is analyzed to see whether the designer needs to be concerned about the selection of exact PR times. Several conclusions were reached on the bases of the review and the analyses. It was concluded that although there has been a great deal of research on PR times, there appears to be some doubt about how well the current values used for highway design purposes represent real-world conditions. Also for applications related to Case III ISD determination PR time has little influence on the overall ISD requirement. On the basis of these conclusions it is recommended that the current values used for PR time for Case III ISD applications be retained because of their validation from several empirical studies and the insensitivity in change of ISD values relative to changes in PR times.

Language: en

Keywords

Accident prevention; Intersections; Traffic signals; Ground vehicles; Highway systems; Transportation personnel; Sensory perception; Structural design